Sony MEX-BT5700U Xplod Bluetooth CD Receiver

Each year car, more and more new cars include built-in connection options for iPods, iPhones, and Bluetooth devices. But if you’re not yet in the market for a new car, you can still get such connectivity via an aftermarket upgrade. Sony’s MEX-BT5700U, a member of the company’s Xplod line of automobile head units—is a solid option that lets you connect both iPods and iPhones.

The MEX-BT5700U is designed to occupy one DIN—a standard unit of measurement for car stereos, about two inches tall by seven inches wide. The vast majority of cars on the road have either a one-DIN or a two-DIN opening in the dash for the audio system. My car, a 2004 Kia Sedona minivan, has a two-DIN spot, so the custom-stereo installer used a spacer pocket to fill and cover the extra space. The unit Sony supplied for this review fit well, with installation taking about an hour.

A CD-R/RW-compatible CD player rests behind the head unit’s faceplate, which can be removed for security (a hard carrying case is included). The system’s AM/FM radio tuner provides 18 FM and 12 AM presets, accessible via face-mounted controls or the included wireless remote. HD Radio—a digital, terrestrial radio format with clearer sound that lets you “tag” songs for later purchase using an iPod—is a $150 option. You can also hook up a satellite-radio tuner using a separate $100 Sony UniLink-bus adapter.

A front-facing USB slot on the head unit lets you connect just about any USB-compatible MP3 player, including—via a USB dock-connector cable—any iPhone, iPod nano, iPod classic, or iPod touch for both playback and charging. Setting the source input to USB lets the head unit read the connected device’s contents and display them on the head unit’s screen. (If you’re using an iPod shuffle or a very old iPod, you’re not totally out of luck, however—there’s also a 3.5mm auxiliary-input jack you can use to input audio from any device with a headphone jack.)

One minor complaint here is that this USB port is in plain sight. This means that when your iPod is connected, there’s a big cable dangling out of the dashboard. Compare this to the Pioneer unit I have installed in my other car, which has a USB port on the back: I’ve snaked the dock-connector cable from the back of the Pioneer unit into the dashboard glove compartment, making the wiring unobtrusive and keeping my iPod hidden from potential thieves when I park.

You navigate your iPod’s music content using either the controls on the head unit or an included wireless remote control. I have a 160GB iPod classic that hosts over 12,000 songs at last check, so navigating using the head unit was clumsy at best. You can use a “Jump” feature to automatically skip forward a specific number of songs on a playlist, but this doesn’t make the navigation of large lists any easier. This unit needs some sort of fast scrolling feature, similar to the way that the iPod will let you scan alphabetically through artist and album lists when you spin the Click Wheel rapidly.

Bluetooth support

If you have a second-generation iPod touch or an iPhone running iPhone OS 3, you also have the option of streaming audio wirelessly over Bluetooth. That’s right—you can have a completely wireless sound system in your car. This is incredibly convenient and worked quite reliably for me once I worked out some kinks on my own iPhone 3G. Using a Bluetooth connection does run down the iPhone’s battery much faster than normal, though.

Pairing your device with the head unit is similar to pairing with a set of Bluetooth headphones or a Bluetooth headset. You enter a code on the source device, enter the code again on the head unit (using the remote control is the easiest way to do so), and the two devices connect. Any time the head unit is powered (in other words, whenthe car is running or in accessory-power mode) and the iPhone or iPod touch is on, they’ll automatically reconnect. You can even link the head unit to more than one device: my iPhone, my wife’s iPhone, and my latest-generation iPod touch were all connected at one point. However, the system will recognize only one source at a time—you change which device the Xplod recognizes as the audio source using the head unit’s Bluetooth menu.

Once paired, you can also use the MEX-BT5700U as a Bluetooth speakerphone for your iPhone. The head unit includes its own wired microphone, which can clip to your dashboard or visor. This allows for totally hands-free calling from your car, and it works pretty well, though the initial installation may involve some trial and error as you and your installer find just the right location for the mic to live. You can adjust the mic gain and the amount of ambient noise cancellation using controls built into the head unit.

While the iPhone initially sees the Sony head unit as a glorified set of headphones, the MEX-BT5700U can do a lot more. For example, set the head unit to Bluetooth Phone source mode, then use the Seek feature (a magnifying glass on the head unit’s controls and remote), and you can either browse or download your iPhone’s contact list. This unlocks a new set of options on the iPhone, under the Sony device’s Bluetooth profile, for selecting specific contact groups to synchronize.

This, for me, is the niftiest part of the whole Sony/iPhone integration experience. At last check I have more than 500 contacts in my phonebook, and only a fraction of them are people who I’d ever dream of calling when I’m in the car. So I created, in Address Book on my Mac, a group called “On the Road”; after syncing that group to the iPhone, and then to the MEX-BT5700U, those contacts are now in the Sony head unit’s phonebook. I can call those people very quickly using the remote control—I never need to get my phone out of pocket or jacket. (Obviously, this is distracting—don’t do it while you’re driving, whatever you do. It’s much safer to pull over to the shoulder of the road or into a parking lot before you make a call. In fact, depending on where you live, there may be a law requiring this.)

Other observations

The head unit provides 52W of power to four speakers, which should be quite an upgrade from most older stock stereos. The system also provides preamp-front, -rear and -subwoofer outputs with low- and high-pass filters. Sony has included extensive audio-tweaking options in the head unit for customizing equalization for each source. You can also adjust the audio level of Bluetooth sources by up to 18dB up or down.

The MEX-BT5700U’s florescent, blue display tends to wash out in direct sunlight, so if you’re in a ragtop or frequently use your sunroof, this head unit may not be the best option for you. This issue makes it difficult to see what’s on the screen, whether that’s the current radio-station frequency, track or artist information on your iPod, or, most important, the ID of an incoming caller. (Blue was an odd choice of display color—besides the issue with washing out, blue isn’t a dashboard-lighting color I see used in a lot of vehicles. When the MEX-BT5700U first debuted, Sony touted a feature for customizing the display colors. Unfortunately, that feature isn’t actually included, although you may still see it in descriptions of the unit from some online vendors—even Sony’s own Website mentioned it long after the system shipped.)

Macworld’s buying advice

Thanks to the awkward placement of the USB connector, the clumsy list navigation, and the lousy display, the MEX-BT5700U isn’t a home run. But Sony deserves credit for the excellent iPod connectivity and (for iPhone and second-generation iPod touch) Bluetooth integration.

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